1. Field of the Invention
The present invention relates to a shield for a needle and more particularly to a safety shield assembly that may be used in conjunction with a syringe assembly, a hypodermic needle, a needle assembly, a needle assembly with a needle holder, a blood collection needle, a blood collection set, an intravenous infusion set or other fluid handling devices or assemblies that contain piercing elements.
2. Description of Related Art
Disposable medical devices having piercing elements for administering a medication or withdrawing a fluid, such as hypodermic needles, blood collecting needles, fluid handling needles and assemblies thereof, require safe and convenient handling. The piercing elements include, for example, pointed needle cannulae or blunt ended cannulae.
Safe and convenient handling of disposable medical devices is recognized by those in the medical arts so as to minimize exposure to blood borne pathogens. Safe and convenient handling of disposable medical devices results in the disposal of the medical devices intact.
As a result of this recognition, numerous devices have been developed for shielding needles after use. Many of these devices are somewhat complex and costly. In addition, many of these devices are cumbersome to use in performing procedures. Furthermore, some of the devices are so specific that they preclude use of the device in certain procedures or with certain devices and/or assemblies.
For example, a number of devices incorporate a pivoting shield assembly in which the shield can be pivoted away from the needle during use and pivoted about the needle after use, for protection from the used needle. U.S. Pat. No. 5,188,611 discloses a reusable safety needle arrangement having a collar for engaging a needle and a slotted longitudinal shield which is attached to the collar at a hinge for pivoting over the needle. The arrangement includes a locking mechanism for locking the shield over the needle, which locking mechanism is provided through a set of flanges on the shield which grip a set of complementary catches on the collar. Such an arrangement is specifically designed to be reusable, such that the locking member can be reversed by pinching the shield to cause the flanges and catches to disengage to release the shield from the collar. Such an arrangement with a reversible locking mechanism potentially exposes a user to a used needle tip, in that the shield can be retracted from the needle after the needle has been used and shielded.
Various mechanisms for locking the shield in place over the needle by direct engagement with the needle have also been developed to prevent re-exposure of the needle. For example, the U.S. Pat. No. 5,188,611 patent further discloses a keeper within the slot of the longitudinal shield, which engages directly with the needle cannula as a locking mechanism. Such a keeper is disclosed as being reversible through manipulation of the mechanism. Further, locking engagement directly with the needle may cause the needle to vibrate, thereby increasing the chances of blood spatter from the needle tip.
In view of the foregoing, a need exists for a shieldable needle assembly that achieves secure and effective irreversible shielding of a used needle cannula which is simple and inexpensive to manufacture and easy to operate.